Elemental phosphorus occurs as tetratomic molecules, P4. What mass (g) of chlorine gas is needed to react completely with 455 g of phosphorus to form phosphorus pentachloride?
We will begin solving this problem by analyzing what information we have, to solve this problem:
Firstly, we will need to write a balanced equation for the data provided.
Phosphorous P4 reacts with Chlorine gas to form Phosphorous Pentachloride.
Recall that, Chlorine gas - Cl2 exists as a diatomic molecule and the prefix -penta refers to 5 therefore, we can say that the following reaction takes place
P4 (s) + Cl2 (g) → PCl5 (s)